I can tell your upset by this craziness. And hope you find some relief. Can you just walk away and not worry about it? I know, easier said than done. But the courts should not get involved 6 times in a month because he keeps changing his mind.
I'd think about saying here are the times the court has awarded you visitation. There will be no modifications without a court order. I can not deal with your constantly changing schedule. You need to make your schedule work around these times.
And be done. if he can't make it, he can't make it. His problem. Not yours.
Be strong. And don't let this guy get under skin. Try to let go.